Fasting blood glucose 9.5mmol / L if you really need to take metformin, the severity of the disease and individual differences, the dose is not the same, generally not more than 2550mg per day. Clinically, the most commonly used is Metformin Hydrochloride tablets, usually the recommended starting dose for adults is 500mg each time, twice a day; if the specification is 850mg once a day, taken with meals. Depending on the severity of their blood sugar and the individual’s sensitivity to the drug, their dosage can be increased, but not more than 2550mg a day. Moreover, in the absence of typical symptoms of diabetes, a fasting blood glucose of ≥7.0 mmol/L at least twice on non-same day is required to confirm a diagnosis of diabetes before treatment with glucose-lowering drugs such as glimepiride and metformin can be considered, along with diet and exercise therapy. Metformin also causes nausea, vomiting, diarrhea, abdominal pain, taste disorders and other side effects, allergies or liver and kidney dysfunction are its contraindications. Therefore, patients should not use the drug alone, and need to go to a professional physician to use the drug, in order to avoid delays in the condition.